Keira Knightley: "Jack Ryan role is lighter"

The Oscar-nominated actress is best known for starring in dramatic period pieces, but she admits she was conscious of her movie choices and decided to sign up for the ''pure entertainment'' action thriller - also starring Chris Pine and Kevin Costner - as a break from her usual fare.

Speaking to the Independent on Saturday's Radar magazine, which is out tomorrow (18.01.14), she explained: ''[I wanted to] do different things, really. I've been doing, over the last five years, an awful lot of very dark pieces of work. I wanted to get to do something that was lighter.

'''Jack Ryan' is popcorn, a pure piece of entertainment. I thought, 'I haven't done a pure piece of entertainment for at least six, seven years.' ''

The 'Anna Karenina' actress still loves period dramas and says she won't apologise for starring in so many of them, including 'Pride and Prejudice' and 'Atonement'.

She said: ''When I was younger I felt like I really was doing something wrong for doing period films. I think I've now got to where I can stop apologising for that bit, and go, 'I love them, I've always loved them, I love doing them.'

''I think it's something to do with me and the way my imagination and fantasy world works - I love that you can just dive into it ... your own world, your own life, your own personality is completely lost because everywhere that you know is taken away and you get to dive into a total fantasy. And I love that.''